Mud flaps are commonly used in conjunction with the rear wheels of pickup trucks, semi-tractor trailers, automobiles, motorcycles and the like to prevent mud, rocks, and other road debris from being launched by the action of the wheels onto the vehicle to which the mud flaps are attached or into the path other vehicles. Mud flaps are typically made of tough, semi-flexible sheets of hardened rubber or similar polymeric materials. Mud flaps also often include a weight affixed at or near the bottom edge of the mud flap in order to keep the flap in place and to give it additional heft so as to deflect downward the heavier debris from the road.
Because mud flaps and their associated mud flap weights are readily seen by other motorists, it is common for mud flaps and mud flap weights to be decorated. Professional truck drivers, especially those who own and operate their own trucking rigs, are known to devote considerable time, effort, and money into customizing the appearance their vehicles. This often includes custom paint jobs and pin-striping, custom wheels, as well as custom-made mud flaps and mud flap weights. Often mud flap weights are customized to include a cut-out silhouette of the a desired shape, such as the name of the truck builder (for example, Peterbilt or Mack) or other words and/or shapes.